Adding specific uv map to UVMap node in python script
If you have enabled Developer Extras in the preferences, you can see the attribute name linked to the field while hovering over it : uv_map

The field is a StringProperty, meaning you have to set it to a str value. It doesn't matter if it doesn't exist yet on the object data. If it doesn't it will be filled with red.
See :
import bpy

uv_map_node = bpy.context.object.active_material.node_tree.nodes.new('ShaderNodeUVMap')
uv_map_node.uv_map = &quot;test&quot;

uv_map_node2 = bpy.context.object.active_material.node_tree.nodes.new('ShaderNodeUVMap')
uv_map_node2.uv_map = &quot;UVMap&quot;